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From: raible@orville.nas.nasa.gov (Eric L. Raible)
Newsgroups: comp.lang.lisp
Subject: permutations
Message-ID: <1131@amelia.nas.nasa.gov>
Date: 17 Oct 88 19:40:00 GMT
Sender: news@amelia.nas.nasa.gov
Reply-To: raible@orville.nas.nasa.gov (Eric L. Raible)
Organization: NASA Ames Research Center, Moffett Field, CA
Lines: 13


(defun permutations (elements)
  (if (null elements)
      (list nil)
      (mapcan
       #'(lambda (element)
	   (mapcar
	    #'(lambda (permutation)
		(cons element permutation))
	    (permutations (remove element elements))))
       elements)))

Comments?  Alternatives?